Numerous robotic moving bodies are available in the prior art for a variety of uses. One example is described in U.S. Pat. No. 4,637,494 which is an apparatus for moving carriages along ladders. In this device, a carriage carrying a robot, television camera, etc. is moved along a ladder having spaced ledges. The carriage has a number of gripper units moved in the direction of movement of the carriage by air cylinders or motor driven threaded rods. Each gripper unit is reciprocated toward and away from the ladder and provided with a motive device for opening and closing grippers for gripping or releasing the ledges.
Another example of an moving robot is described in U.S. Pat. No. 4,674,949 which is described as a robot with climbing feet. This patent discloses a mobile robot which is able to cling. The example illustrated shows a vehicle with two cooperating trains, each of which has four feet. Locomotion is achieved by placing four feet of the first train down and lifting the second train. The lifted train is moved along a rail into a new position where it comes into contact with the ground and becomes the new base. The train has suction cups for feet and attaches to the ground, then repeats the process by moving the first train in the same manner. The purpose of this invention is for horizontal locomotion.
A third example is described in U.S. Pat. No. 4,940,382 which is titled "An autonomous moving body for transporting a tool at a constant speed". This patent discloses three cooperating components to provide constant velocity linear motion. Two of the components have attachment feet while the third rides back and forth along a track. The two mechanisms with feet move one at a time providing a jerky motion of stop and go. The third evens the motion by moving when the base is still.
All of the prior art robotic moving devices, while useful to a degree, are limited in their ability to adapt to a changing terrain. For example, the device described in the '494 patent is limited to ladders, and the devices described in the other two patents are limited to relatively smooth surfaces such as the skin of an aeroplane. None of these three devices has the ability to curve to the left or right or to curve up and down. And none of these devices is able to twist its body to go from a surface on one plane to a surface on another plane.